A power device has been widely used as a component for various kinds of power supplies or for electric devices of motor vehicles, or as a component for electric devices of industrial machines. As compared with a typical semiconductor device, the power device has a high breakdown voltage and a high current, and also has a high speed and a high frequency depending on an application thereof. Examples of the power device include an IGBT, a diode, a power transistor, a power MOS-FET, a thyristor, and the like. When these power devices are selected as high quality products through measurement of electrical characteristics (static characteristics and dynamic characteristics) thereof, they come into the market depending on applications thereof.
A probe apparatus has been widely used as a testing apparatus configured to measure electrical characteristics of a semiconductor device such as a memory device or the like while a power device is not separated from a wafer. The probe apparatus typically includes a loader chamber and a prober chamber adjacent thereto. While a wafer is transferred into the loader chamber, pre-alignment is carried out, and after electrical characteristics of the wafer loaded from the loader chamber are measured in the prober chamber, the measured wafer is returned back to the loader chamber. Recently, various technologies for applying such a probe apparatus to measurement of electrical characteristics of a power device have been developed, and a probe apparatus that measures static characteristics, such as resistance or the like, of a power device has been developed and commercialized.
FIG. 4 is a conceptual diagram showing an example of a conventional probe apparatus. FIG. 4 illustrates a prober chamber of a probe apparatus configured to measure static characteristics of a power device at a wafer level.
As depicted in FIG. 4, the prober chamber includes a movable mounting table 1 configured to mount a wafer W thereon, and a probe card 2 provided above the mounting table 1. On a surface of the mounting table 1, a conductive film electrode 3 (shown as a thick line in FIG. 4) made of a conductive metal such as gold or the like is formed. This conductive film electrode 3 is electrically connected to a tester 5 via a measurement line 4 (for example, cable).
If the probe apparatus depicted in FIG. 4 measures static characteristics of a power device at a wafer level, when the wafer W is mounted on the mounting table 1, a collector electrode of the power device on a lower surface of the wafer W is brought into electrical contact with the conductive film electrode 3 of the mounting table 1. When the probe card 2 is brought into contact with this wafer W, a gate electrode and an emitter electrode of the power device are electrically connected to multiple probes 2A. In this state, if a voltage is applied from the probe 2A to the gate electrode of the power device, a high current flows from the tester 5 to the measurement line 4, the conductive film electrode 3, the collector electrode, and the emitter electrode. In this case, static characteristics, such as resistance or the like, of the power device are measured via other probes 2A. Further, in FIG. 4, the probe card 2 is fixed to a head plate 6 via a clamp device (not illustrated).
As described above, a probe apparatus that measures static characteristics of a power device has been commercialized. However, a probe apparatus configured to measure dynamic characteristics of a power device is still under development and does not reach a level of commercialization. For this reason, dynamic characteristics of a power device need to be measured during a packaging process, and if a package product is evaluated as a defective product, it is wasted. Therefore, production yield of a power device as a product is deteriorated, so that defective products are likely to be produced.
Further, the present applicant developed a probe apparatus capable of measuring dynamic characteristics of a power device based on the probe apparatus depicted in FIG. 4 (see Patent Document 1). That is, in the probe apparatus described in Patent Document 1, the same measurement line as the measurement line 4 depicted in FIG. 4 is provided at the mounting table of the probe apparatus, so that both of static characteristics and dynamic characteristics of the power device can be measured with a single probe apparatus.